Asphalt road paving machine(s) (“asphalt paver(s)”) include a tractor with a hopper, a feed conveyor and an auger. The hopper is typically located at the front of the asphalt paver, and receives and holds asphalt paving material. The feed conveyor delivers the asphalt paving material to the spreader auger at the rear of the paver. The auger distributes the asphalt, laterally behind the tractor, to the road surface in front of a screed assembly.
Asphalt pavers also include the screed assembly, a heavy assembly drawn behind the asphalt paver by a pair of pivotally mounted tow arms. The screed assembly smoothes out and compresses the asphalt material that has been spread by the auger. The screed assembly may include a screed extender frame for adjusting a main screed width.
Road mat thickness is determined in part by asphalt material composition, machine specifics, as well as by the volume of the asphalt material pile placed in front of the screed. Asphalt material composition and screed specifics are typically constants with a specific machine and mix; however, the height of the material pile must be provided by the conveyor and auger before the asphalt paver starts and moves forward, and then as the asphalt paver continues to move forward. Material pile height should remain constant to pave an even surface. Sensors help determine the amount of material in front of the screed.
At the start of paving, the area around the auger (in front of the screed) typically is empty. In order to have a constant material mat height, as opposed to a sloped hill, bump or cavity, a sufficient level of asphalt material should be loaded into the area around the auger and be spread at that level the width of the desired paving section. Typically the conveyor and auger are run prior to movement of the asphalt paver to pre-fill the auger chamber of the asphalt paver. Because the asphalt paver is not moving, this process sometimes leads to undesirable effects such as asphalt segregation or asphalt being pulled underneath the machine by the conveyor. Movement of the machine during this initial time can lead to the uneven pavement.
U.S. Pat. No. 8,469,630 (“Olson et al.”) issued Jun. 25, 2013 describes a sensor system for road construction equipment. The system includes a conveyor for transporting material to an auger. A feeder sensor associated with the conveyor communicates the height of the material on top of the conveyor such that a master controller can regulate the amount of flow of material to the conveyor. The disclosure does not address pre-filling of the auger chamber to ensure that the mat laid down by the paving machine is constant and even from the start of paving. A better design is needed.